Speedometer construction



ct. 0 1927 J. .M. LEA

SPEEDOMETER CONSTRUCTION Filed July 9. 1925 a I Ma Patented Get 11, 1927.

UNITED'STATE'S P T NT oF ms-Q JOHN M. LEA, OF DETROIT, MICHIGAN, ASSIGNOR TO THE MILEOMETER COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

srnnnoivrnmnn CONSTRUCTION.

Application filed July 9,

My invention relates to improved speedometerconstructions and more particularly to means for calibrating the indicating mechanism of the same so that it will be accurate and reliable at all times. The invention has among its other objects the production of a device of the kind described that is simple, convenient, compact, durable, reliable, accurate, neat, eflicient and satisfactory for use wherever found applicable.

Many other objects and advantages of the construction herein shown and described will be obvious to those skilled in the art from the disclosure herein given.

To this end my invention consists in the novel construction, arrangement and combination of parts herein shown and described, and more particularly pointed out in the claims.

In the drawings, wherein like reference characters indicate like or corresponding parts:

Figure 1 is a vertical section taken through my device;

Figure 2 is a section taken substantially on the line 22 of Figure 1;

Figure 3 is an enlarged detail of the calibrating device; and

Figure 4 is a section takensubstantially on the line 4i-4 of Figure 3.

Referring to the drawings, wherein I have illustrated the preferred embodiment of my invention, 1 indicates a casing of suitable size, shape or material for the speedometer mechanism, and in the presentv instance I have also shown an odometer mechanism within the same casing and operated simultaneously with the speedometer. A drive shaft 2 extends through the casing and through which the drive from the vehicle (not shown) is obtained. An impeller or fan 3 is secured at the inner end of the drive shaft 2, the same operating within a stationary annular wall 5 about its periphery, and slots or openings 4 are formed at the bottom or web of said member 5 and through which the air is admitted to the intake side of said impeller fans or blades.

A bracket or support 6 is secured to the casing, and rotatably supports an indicator wheel or dial 7. The indicator wheel has vanes 8 at its inner side, said vanes being spaced apart and having apertures 9 there- 1923. Serial No. 650,463.

between, and when the indicator wheel is mounted in the position shown by Figure 1,

the rotation of the impeller 3 will drive air through the openings 9 to partially rotate the indicator'wheel 7.

- A can 12 is carried by the indicator and extends inwardly from the peripheryof the indicator wheel to substantially the rotatable axis thereof, as shown more particularly in leaf spring 13 is secured rigidly at one end to a stationary part of the device, as at 15, the free end of said spring preferably having an anti-friction member 14 thereat to slida-bly engage the cam surface of the cam 12. An arcuate elongated slot 10 is formed in the indicator wheel as shown, and cooperates with a stationary abutment 11 to limit the movement of said indicator wheel at the opposite ends of travel.

In order to accurately calibrate the device so that the readings thereof will be of correct scale contour and true and reliable at all points in the scale range, I have arranged a member 16 to cooperate with the spring 13 as shown, said member 16 secured rigidly to a stationary part of the device as by screws 17 or the like, and having teeth or fingers 18 spaced therealong and extending therefrom so as to project into the path of movement of the spring, as shown more clearly in Figure 2.

The fingers 18 are formed somewhat in the nature of the teeth of a comb, and the member is made preferably of a sheet of soft brass (twenty gauge stock having been found suitable), out of which the fingers are punched. When arranged in the, manner shown in the drawings, the fingers may be individually adjusted by bending or straightening them either toward or from the spring 13 as is found desirable, This adjusting device is extremely economical of manufacture, and has been found to be exceedingly simple and reliable in use and operation,

aving thus described my invention, it is obvious that various immaterial modifications may be made in the same without departing from the spirit of my invention; hence I do not wish to be understood as limiting myself to the exact form, construction, arrangement and combination of parts herein shownvand described, or uses mentioned.

Vhat I claim as new and desire to secure by Letters Patent is: a

1. In a device of the kind described and in combination, a speed-indicating means having a cam carriedth'ereby, drive means for actuating said indicating means, a leaf spring fixed at one end and engageable with said cam at said other end so as to retard and retrieve said indicating 'means, and

calibrating means, comprising a stationary member having spaced fingers projecting in the path of said spring so as to'be successively engaged thereby and made of a relatively soft material so that the individual fingers may be, adjustably bent toward or r from said spring and retain their position as desired. 7 V r y 2., In a device of the kind described and in combination, a -*speed-indicating means having a cam carried thereby, drive means for actuating saidindicating means, a. leaf spring fixed at oneend andengageable With signed my name.

said cam at said other end so as to retard and retrieve said indicating means, and calibrating means comprising a stationary member substantially parallel to said spring and having bendable fingers projecting in the path of the spring adapted to be successively and simultaneously engaged thereby as the spring is bent from its normal position, said fingers adapted to bebent towards or away from the spring.

3. In a device of the character described and in combination, a speed indicating means having a cam carried thereby, drive means for actuating said speed indicating means,

a leaf spring fixed at one end andengageable with: said cam at the other end so as to retard and retrieve the indicating means, and calibrating means comprising a stationary member formed with bendable portions disposed in the path of m0vement of said spring. f

In testimony whereof, I have hereunto 1 JOHN M. LEA. f 

